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<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>

</body>
<script>
  "use strict";
  // 判断对象是否存在某属性的常用方法
  let test = {
    name: "cz",
    age: 19
  };

  // 1. .点或括号[]
  // 2. in运算符(无法判断属性在自身或原型链上)
  // 3. hasOwnProperty()
</script>

</html>